A conventional “dimmer” is a device that is used to vary the brightness of light generated by a lighting device. Historically, dimmers have been used perhaps most commonly with incandescent lighting devices, wherein the dimmer is employed to vary the average power provided to the lighting device, and the resulting brightness of light generated by the lighting device varies in relation to the power provided to the lighting device. More specifically, a conventional dimmer typically is coupled to an input signal that provides a source of power (e.g., an A.C. “mains” or line voltage such as 110 VAC or 220 VAC). An output of the dimmer is coupled to the lighting device and may be varied between essentially zero and a maximum value corresponding to the input signal (i.e., between essentially zero and 100% of available power), in response to some user-variable control mechanism associated with the dimmer. By increasing or decreasing the RMS voltage of the dimmer output and hence the mean power provided to the lighting device, it is possible to vary the brightness of the light output between zero (i.e., light off) to full on.
Dimmers range in size from small units having dimensions on the order of a normal light switch used for domestic lighting, to larger high power units used in theatre or architectural lighting installations. Small domestic dimmers generally are directly controlled via some user interface (e.g., a rotary knob or slider potentiometer), although remote control systems for domestic and other uses are available. For example, “X10” is an industry standard communication protocol for home automation applications to facilitate remote/programmed control of a variety of devices including dimmers (X10 was developed by Pico Electronics of Glenrothes, Scotland). X10 primarily uses power line wiring for control signals that involve brief radio frequency bursts representing digital information, wherein the radio frequency bursts are superimposed on the line voltage and used to control various devices coupled to the power line, such as dimmers. In particular, via the X10 communication protocol, an appropriately configured dimmer may be remotely controlled to vary the light output of a lighting device coupled to the dimmer at virtually any level between full off and full on. Using the X10 protocol, multiple dimmers configured to receive X10 control signals may be deployed in a given environment and controlled remotely.
In addition to some domestic and other architectural applications, a number of dimmers also may be employed in entertainment venues (e.g., theaters, concert halls, etc.) to facilitate variable brightness control of several lighting devices (e.g., used to provide stage lighting). Multiple dimmers deployed in such environments (as well as other controllable devices) may be controlled in a networked fashion via a central control interface (sometimes referred to as a control “console”) using a communication protocol commonly referred to as DMX512 (often shortened to DMX). In the DMX protocol, dimming instructions are transmitted from the central control interface to multiple dimmers as control data that is formatted into packets including 512 bytes of data, in which each data byte is constituted by 8-bits representing a digital value of between zero and 255. These 512 data bytes are preceded by a “start code” byte. An entire “packet” including 513 bytes (start code plus data) is transmitted serially at 250 kbit/s pursuant to RS-485 voltage levels and cabling practices, wherein the start of a packet is signified by a break of at least 88 microseconds.
In the DMX protocol, each data byte of the 512 bytes in a given packet is intended as a dimming instruction for a particular dimmer, wherein a digital value of zero indicates no power output from the dimmer to the lighting device (i.e., light off), and a digital value of 255 indicates full power output (100% available power) from the dimmer to the lighting device (i.e., light on). Thus, a given communication channel employing the DMX protocol conventionally can support up to 512 addresses DMX dimmers. A given DMX dimmer generally is configured to respond to only one particular data byte of the 512 bytes in the packet, and ignore the other packets, based on a particular position of the desired data byte in the overall sequence of the 512 data bytes in the packet. To this end, conventional DMX dimmers often are equipped with an address selection mechanism that may be manually set by a user/installer to determine the particular position of the data byte that the dimmer responds to in a given DMX packet.
Some examples of commercially available DMX dimmers include the DMX-1 or DMX-4 Dimmer/Relay Packs manufactured by Chauvet of Hollywood, Florida (see www.chauvetlighting.com; the DMX-1 User Manual at www.chauvetlighting.com/system/pdfs/DMX-1_UG.pdf is hereby incorporated herein by reference). These products may be operated to provide gradually variable output power between zero to 100% based on a corresponding input DMX command that may vary between digital values of zero and 255. In one mode of operation, these products may be selected to function as an addressable controllable relay, wherein full power output is provided when the received DMX command exceeds 40% (i.e., a digital value of greater than 102), and zero power is provided for incoming DMX commands less than 40% (i.e., a digital value of less than 102).
In some lighting applications, an Ethernet protocol also may be employed to control various lighting devices, including dimmers. Ethernet is a well-known computer networking technology for local area networks (LANs) that defines wiring and signaling requirements for interconnected devices forming the network, as well as frame formats and protocols for data transmitted over the network. Devices coupled to the network have respective unique addressess, and data for one or more addressable devices on the network is organized as packets. Each Ethernet packet includes a “header” that specifies a destination address (to where the packet is going) and a source address (from where the packet came), followed by a “payload” including several bytes of data (e.g., in Type II Ethernet frame protocol, the payload may be from 46 data bytes to 1500 data bytes). A packet concludes with an error correction code or “checksum.” Some dimming control systems involving multiple dimmers may be configured for control via an Ethernet protocol, or include multiple layers of control involving both Ethernet and DMX protocols. Some examples of such systems are provided by Electonic Theatre Controls (ETC) of Middleton, Wis. (see www.etcconnect.com), including model “CEM+” control modules and model “Sensor+” dimmer modules designed to operate based on input control signals formatted according to Ethernet or DMX protocols.
In yet other lighting applications, the Digital Addressable Lighting Interface (DALI) protocol also may be employed to control various lighting devices, including dimmers. The (DALI) protocol has been employed extensively primarily in Europe and Asia to facilitate variable brightness control of multiple fluorescent lighting devices via addressable ballasts coupled together in a network configuration and configured to be responsive to lighting commands formatted according to the DALI protocol. Conventionally, a digital fluorescent lighting network employing a DALI protocol is based on digital 120/277V fluorescent electronic ballasts, typically available in one- and two-lamp models that operate linear T5, T5HO and T8 fluorescent lamps as well as compact fluorescent lamps. DALI-based ballasts and controllable dimmers also are available for high-intensity discharge (HID), incandescent and low-voltage halogen systems.
As with DMX- or Ethernet-based lighting networks, each controllable device in a DALI-based network is given an address so that it can be individually controlled or grouped in multiple configurations. One or more DALI-compatible control device(s) are then coupled to the network of interconnected controllable ballasts/dimmers to control lighting functions across the network. Examples of such DALI-compatible control devices include local wall-mounted controls that enable manual push-button switching to select programmed dimming scenes, a computer for centralized lighting control, local PCs for individual occupant control, as well as occupancy sensors, photosensors and other controls.
In one exemplary implementation, from a central PC configured to communicate with devices pursuant to the DALI protocol, a user/operator (e.g., lighting manager for a facility) can individually address each DALI-based ballast in a building or gang them in groups, then program each ballast or group to dim from 100% to 1% either on a scheduled basis or in reaction to preset conditions, such as available daylight. In another aspect, the DALI-based controllable ballasts/dimmers themselves may provide information back to a control device such as a PC, which information may be used to identify lighting device and/or ballast failure and generate general energy consumption information. Some common examples of DALI-based lighting network deployments include small and open offices where users can control their own lighting, conference rooms and classrooms that require different lighting scenes for multiple types of use, supermarkets and certain retail spaces where merchandising and layout changes frequently, hotel lobbies and meeting spaces to accommodate times of day, events and functions, and restaurants to match the lighting to time of day (breakfast to lunch to dinner). DALI-based components, including controllable ballasts/dimmers, are available from several manufacturers, some examples of which include Advance Transformer, Osram Sylvania (Quicktronic DALI dimming ballasts), Tridonic (DigialDIM and other products), HUNT dimming (Eclipsis PS-D4), Leviton (CD250 DALI Dimming/Scene Controller), and Lightolier Controls (Agili-T network/fixtures).
Yet other lighting applications relating to dimming may provide for dimming and brightness control via proprietary communication protocols other than the DMX, Ethernet or DALI examples discussed above. For example, Lutron Electronics, Inc. (www.lutron.com) provides a variety of systems under the name “GRAFIK Eye®” that implement preset lighting brightness conditions in multiple lighting zones via programmed control of multiple dimmers (see www.lutron.com/grafikeye/). The Lutron GRAFIK Eye® systems typically receive lighting control commands that are formatted according to a proprietry Lutron GRAFIK Eye® protocol, wherein the lighting control commands correspond to various preset lighting brightness conditions in different lighting zones. In one implementation, lighting control commands for the Lutron GRAFIK Eye® systems are generated via a personal computer (PC) running proprietary Windows™ based software. In some implementations, the GRAFIK Eye® systems alternatively may be configured to process lighting control commands that are formatted according to a DMX protocol.
In addition to merely varying the brightness of light generated by a lighting device, some types of lighting devices may be configured to generate different colors of light, wherein both the color and the brightness of light generated at any given time may be varied. One example of a multicolor lighting device based on LED light sources that may be controlled via lighting commands formatted according to a DMX protocol so as to vary the color and/or brightness of generated light is described in U.S. Pat. No. 6,016,038, entitled “Multicolored LED Lighting Method and Apparatus,” hereby incorporated herein by reference. In some implementations, such multicolor lighting devices also may be controlled by lighting commands formatted according to an Ethernet protocol; for example, in one implementation, a “translation” device may be employed that receives lighting commands formatted according to an Ethernet protocol from a local area network and translates the Ethernet lighting commands to lighting commands formatted according to a DMX protocol, which are in turn processed by the lighting device so as to control the color and/or brightness of the generated light.
Because the DMX or Ethernet-based multicolor lighting devices described above need to receive both operating power and lighting commands, generally these types of lighting devices require multiple electrical connections (including multiple wires, cables, and/or connectors, or multiple contact/pin connectors) to accommodate the provision of both the operating power and the lighting commands to the lighting device. Accordingly, these types of lighting devices generally cannot be employed in conventional types of lighting sockets (or lighting fixtures including conventional sockets) that provide only operating power to the device (some examples of such conventional sockets include, but are not limited to, incandescent Edison base screw-type sockets, halogen or MR-16 bi-pin sockets, fluorescent sockets, etc.).
However, other types of variable color lighting devices suitable for a variety of applications have been implemented that require only a conventional power source (e.g., an AC line voltage), and accordingly may be configured for use with conventional types of lighting sockets or lighting fixtures equipped with conventional sockets. In one aspect, such lighting devices may be further configured such that a color or other property of light generated by the device may be changed in response to one or more interruptions of power provided to the device. Examples of such lighting devices are described in U.S. Pat. No. 6,967,448, entitled “Methods and Apparatus for Controlling Illumination,” hereby incorporated herein by reference. Such lighting devices may be coupled to a source of power via one or more switches that are conventionally employed to turn the lighting device(s) on and off (e.g., a standard wall switch). However, beyond merely turning the lighting device(s) on and off, the switch(es) may be further employed to generate one or more “power cycles,” or periodic interruptions of power (e.g., on-off-on power transitions) having particular durations, which in turn affect some aspect of light generated by the lighting device. For purposes of the present disclosure, such lighting devices are referred to accordingly as “power cycle control” lighting devices.
More specifically, in one exemplary implementation, a power cycle control lighting device may include a controller (e.g., a microprocessor) configured to monitor the power provided to the device so as to detect one or more power cycles, in response to which the controller takes some action that affects the generated light. For example, while power is applied to the lighting device, the controller may be particularly configured to detect a power cycle (an on-off-on transition having a predetermined duration) and respond to the power cycle by changing the color and/or some other property of the generated light.
In some implementations, power cycle control lighting devices may be equipped with memory in which is stored one or more pre-programmed lighting control signals, or sequences of lighting control signals constituting lighting programs, that when executed by the lighting device controller provide a variety of possible states for the light generated by the lighting device. For example, one or more particular lighting control signals or programs stored in the memory may dictate a corresponding static color or brightness level of generated light, while other control signals or programs may provide for dynamic multicolor lighting effects. In response to a power cycle, the controller may be configured to select one or more pre-programmed control signals stored in the memory, select and execute a new lighting program from memory, or otherwise affect the light generated by the lighting device. In one exemplary implementation, multiple lighting programs may be stored in the memory, and the controller may be configured to select and execute a new lighting program based on a succession of power cycles. In this manner, a user operating the one or more switches that apply power to the lighting device may sequentially toggle through the available lighting programs by turning the switch from on to off to on again (within a predetermined duration) a number of times until a desired program is selected, at which point the switch may be left in the “on” position to permit execution of the selected lighting program.